21263885 has 4 divisors (see below), whose sum is σ = 25516668. Its totient is φ = 17011104.

The previous prime is 21263867. The next prime is 21263897. The reversal of 21263885 is 58836212.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 4338889 + 16924996 = 2083^2 + 4114^2 .

It is a cyclic number.

It is not a de Polignac number, because 21263885 - 2¹² = 21259789 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2126384 + ... + 2126393.

It is an arithmetic number, because the mean of its divisors is an integer number (6379167).

Almost surely, 2^21263885 is an apocalyptic number.

It is an amenable number.

21263885 is a deficient number, since it is larger than the sum of its proper divisors (4252783).

21263885 is an equidigital number, since it uses as much as digits as its factorization.

21263885 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4252782.

The product of its digits is 23040, while the sum is 35.

The square root of 21263885 is about 4611.2780224142. The cubic root of 21263885 is about 277.0432276674.

The spelling of 21263885 in words is "twenty-one million, two hundred sixty-three thousand, eight hundred eighty-five".